Most electric load controlling systems use two three-way mechanical switches to receive on and off inputs from any one of the switches. In a three-way switching arrangement, two single-pole double-throw (SPDT) switches have power at all times in one of the two legs.
A conventional mechanical three-way switch wiring 100 is illustrated by FIG. 1. The switches S1 and S2 are not wired in the same way from the view of connecting to the main AC wire. The SPDT switch S1 includes a pole 102 connected to a Hot terminal 104 all the time to receive power from an AC power source. The SPDT switch S2 includes a pole 106 connected to an electrical load 108 (e.g., a light bulb, etc.) to turn on or off the electrical load 108 depending on the states of the switches S1 and S2. The switch S2 does not always receive AC power due to different states of the two switches S1 and S2.
Most smart three-way switches currently on the market are using such wiring shown in FIG. 1, which requires identifying the Hot terminal of the AC power source and connecting the pole of one of the three-way switches to the identified Hot terminal all the time to ensure the internal circuitry to have power supply, which is selectively delivered to the connected electrical load. Hence, users often need to rely on “try and error” to figure out a correct Hot terminal to be connected to the wiring box, or need to hire a technician to install the three-way switches correctly, which is time consuming and costly.
Therefore, there is a need for a system for plugging in or hooking up three-way smart switches without identifying a Hot terminal of an AC power source.
The background description provided here is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.